You can breathe a sigh of relief. All that tossing and turning spent wondering when someone was going to create the world's most expensive jelly robot is over: Bompas and Parr have done it.

If you're familiar with the pair you might know that they excel at fantastical, Wonka-esque feats of culinary extravagance such as building a crazy golf course made of cake on the roof of Selfridges. Their jelly robots however, which have been made in celebration of the end of the Sony Xperia Unleashed promotional campaign (a momentous occasion), demonstrate a different skill: that of adding so many costly ingredients to a dish that it becomes the "world's most expensive". It's not a hard task. I could make a bowl of cereal right now and fill it with panda milk and diamonds and it would be the most expensive bowl of cereal in the world. It would also be entirely inedible, but that's not really the point is it?The jelly robots, of which there are three to be "discovered" (they are hidden someone around the UK), include white truffle valves, gemstones for eyes, pistachio and platinum microchips, ambergris honey milk circuits, orchid infused switches, saffron and lychee buttons, a real meteorite and golden cogs. And just so you don't have to slum it when it comes to actually eating it, it comes with a golden spoon.

In a food culture increasingly focused on local provenance and sustainability, the idea of a dish being feted for being "the most expensive" anything is just crass. It should have gone the way of pagers and laserdiscs, but instead it's popping up with increasing frequency. In the last few months alone we've been introduced to the world's most expensive scotch egg which includes beluga caviar and layers of edible gold leaf, while the cruise liner company Silversea have announced that they are to serve a risotto with edible gold leaf, "the world's most expensive ingredient", in their Le Champagne restaurants.

While these dishes are mostly modern creations, the use of gold leaf is not: in fact it's been used in food for centuries. In the ancient cultures of Asia and the Middle East as well as in medieval Europe gold was thought to have mystical and medicinal properties in addition to being a sign of wealth and hospitality. It appears as far back as the 16th century in Goldwasser, the gold-flecked liqueur still around today, and in Britain in recipes such as Elizabeth Raffald's dish of "Gilded Fish in Jelly" in her book "The Experienced English House-Keeper" which dates from 1786.

Food historian Dr Annie Gray points out that part of its appeal was its spectacle. "It's been used an awful lot in the past because it's reflective, and ... tables tended to be lit with candlelight and also firelight, so anything you could use that reflected the light was a good thing." She adds that today we're missing that crucial bit of sensory impact, and notes that "now we look at it and think it's a little bit over the top."

In modern cooking, then, edible gold is meant to signify extravagance and provide an excuse to charge heinous amounts, but actually it just smacks of pretension and trying too hard. But we know this, and that's why it's not everywhere. You'd expect that if gold were a genuinely popular ingredient and the world's most expensive dishes were actually ever sold to anyone other than those whose only money worry is how to spend it, we'd see a lot more of it.

Instead, a large proportion of dishes found on "world's most expensive" lists are one-off marketing tie-ins. Having brought in plenty of customers to eat in the restaurant that serves the "world's most expensive jacket potato" (none of whom actually order the the world's most expensive jacket potato) the dish disappears. Like the historic use of gold leaf, the idea behind these dishes is money: except instead of showing it off, the primary aim today is to make it.